There is disclosed in U.S. Pat. Nos. 3,826,068 and 3,859,776 issued to George C. Ballas and Thomas N. Geist, apparatus for cutting vegetation. Such apparatus in general comprises a rotatable head from which extends at least one length of a flexible non-metallic line. This line is drawn from a spool removably housed within the head, and passes through an opening in the side of the head. On rotation of the head, the extending line engages and cuts the vegetation.
In order to most effectively perform its cutting function, the length of line extending from the housing should be of a prescribed length. During operation, the line is exposed to wear and damage. Consequently, it is necessary from time to time to draw additional line from the spool. With the arrangement disclosed in U.S. Pat. No. 3,859,776, the spool is locked with respect to the rotatable head. Therefore, in order to unwind line from the spool, it is necessary either to (1) detach the spool from the head, release the desired length of line and then re-secure the spool to the head; or (2) with the spool locked in place, grasp the free end of the line and pull additional line past the flange of the spool.
Obviously, complete removal of the spool is a substantial inconvenience, and in the case where additional line is drawn from the locked spool, and must pass through a particular opening in the side of the rotating head, the line has to be trimmed to obtain the correct length. It has been found that from 30 to 50% of the spooled line is wasted as a result of such trimming.
In the arrangement of U.S. Pat. No. 3,826,068, line length can be adjusted without removing the spool, but this involves complex mechanical structure wherein the line is dispensed in incremental lengths rather than by continuous removal which permits an exact amount of line to be withdrawn from the spool. Thus, such a known arrangement is expensive structurally and also is wasteful.